Positive-valve-control mechanism



June 9, 1925. '1,541,081'

P. H. E. VAREILLE Melt/@f P. u

Patented June l9, 1925;.

UNITEDA STATES PATAEN crates.,

OSITIVE-VA'LVE-CONTROL IvECI-IANISM. i

Application flied May 2s, 1921i. serial Numana?.

' opening and the closing of the valve being positivelycontrolled by the said cams. In the known devices of this class, the pivoting axle pin of the rocking lever is stationary,

and for this reason it is practically impossible to obtain the tight closing of the valve.

rlhe present invention has for its object a device of this class providing for the fluid tight closingof the valve, and which is.

chiefly characterized in that the pivoting axle pin `of the rocking lever is carried by a movable support which is yieldingly mounted upon the cylinder head of the enngine, whilst an adjustable stop-piece limits the movement of the said axle pin under the action of the said support, the adjustment of the said stop-piece being such that in the closing position of the valve a slight play is provided between the .axle pin and said stop-piece. y ,l

This arrangement provides for the Huid tight closing of the valve in all cases by the elastic pressure of the valve upon its seat, while on the other hand for the opening of the valve under the positive control, the pivoting axle pin of the rocking lever comes immediately into contact with the adjustable stop-piece, and from this time onward the device will operate in the known manner. Other features of the invention will be set forth in the following description.

The appended drawings show by way of example an embodiment of the said invention.

Fig. 1 is an elevational view of the device with the valve closed, the cylinder and the cam shafts being shown lin section, 'and Fig. 2 is a like view with the valve open.

Fig. 3 is a vertical axial section on line A-A of Fig. 1, and

Fig. 4c is a vertical section on line BB of Fig. 1, showing the connection between the valve stem and the rocking lever.

The stem 1 of the valve 2 is slidable in a guide 3 formed in the cylinder head and is connected with one end t of the rocking lever 5 whose other end 6 is engaged between a cam 7 and a coacting cam 8 which have for example the outlines shown in Figs, 1 and 2, said cams being mounted respecltively upon the shafts 9 and 10 rotating at the same speed. At the middle of the said rocker arm is mounted a pivoting axle pin 11 resting upon a support 12 adapted to slide on a vertical rod 13 which is rigidly secured to the cylinder head; a spring is interposed` between the cylinder head and a shoulder 15 provided uponthe said support, vso that the latter shall be upwardly impelled in a constant manner. In order to allow the motion of the axle 11 underthe action of the spring 111, the Vsaid axle pin extends through an elongated slot 16.

formedin the rod 13. n l p The ascent of the axle pin with its support is limitedby anadjustable Stop-nut 13 Awhich is screwed upon a screwthreaded portion 18 of the rod 13, and is held in the desired position by a lock-nut 19 screwed uponrthe screwthreaded upper end of the rod 13. The position ofthe nut 17 is so adjusted that in the closing position, as shown in 1, a slight play 21 is allowed between the upper generatrix of the axle,

pin 11 and the lower edge of the nut 17. rIhe end tof the rocking lever and theupper end of the valve stem have a ball shape and are connected together by the two plates 23, 24 which have corresponding recesses for the said balls an-d are secured together by a bolt 25 'and a nut 26.-

The operation is as follows:`

I/Vhen the valve is closed, Fig. 1, the end G of the rocking lever is held between the circular profiles of the cams 7 and 8, In these conditions, the said lever willcpivot upon the fixed end 6 under the action of the support 12 which is urged upwards by v spring, and the valve is caused to bear upon its seat in an elastic and fluid-tight manner.vv 

